Stencil fabric and process of producing the same.



ALBERT E. STRIPPEL, OF NEW YORK, N. Y.

STENCIL FABRIC AND PROCESS OF PRODUCING THE SAME.

icense.

Specification of Letters Patent.

Patented Jan. 25, idtti.

No Drawing. Original application filed July 1, 1913, Serial No. 776,893. Divided and this application filed February 17, 1914. Serial No. 819,296.

T 0 all whom it may concern:

Be it known that I, ALBERT E. STRIPPEL, a citizenof the United States, and resident of the borough of Manhattan, in the city and State of New York, have invented a new and useful Improvement in Stencil Fabrics and Processes of Producing the Same, of which the following is a specification.

The objects of my invention are to produce a stencil fabric which will be very durable and sufficiently strong to withstand the severe treatment to which it is subjected in use; which will prevent the type for cutting the stencils from cutting completely through the fabric and blocking out closed characters and which will provide a clear print.

The fabric which is most suitable to be treated to render it desirable as a stencil fabric is a long fiber fabric such as is commonly used in this art, as, for instance, Japanese dental paper. This fabric may be used either in a' single thickness or a multiple thickness as desired and it is pasted along one edge in the usual manner upon a suitable holder of waterproof material for convenience in handling the fabric during its treatment. After the fabric has been completed ready for use, it may be cut into the required sizes for use and cemented on the usual cardboard or fiber frames.

The stencil fabric consists of a long fiber fabric provided with a hygroscopic film rendered impervious to the action of the oils contained in printing inks. While this would produce a stencil fabric which could be used for a short time still to produce a durable stencil, it is necessary to keep this film in a soft and pliable state and also to protect it from deterioration for otherwise it would become brittle. and crack when handled or run through an addressing machine and it would also be subject to decay. This stencil fabric has heretoforebeen treated with an organic oil and a preservative, as, for instance, glycerin and formaldehyde.

The object of this invention is to produce a stencil fabric which will be superior to those heretofore produced as to pliability, durability, and strength. This result is accomplished by the use of metallic salts which are perfectly soluble in water and inorganic acids but not in organic oils, so that they will not be affected by the ink soluit from the action of light which makes the process very difiicult and expensive. I have discovered that by the use of a hydroscopic nitrate, such as sodium nitrate, I can expose the solution to the light and yet keep the specific gravity of the solution practically constant, for the reason that the nitrate has the effect of materially retarding the setting of the film. The nitrate is not affected by the setting of the film and in the finished product it aids in keeping the paper moist by drawing moisture from the atmosphere along with the chlorid. It also preserves the paper from deterioration by the 'action of microbes which is the only natural process by which the gelatin and glycerin can be destroyed.

In producing a stencil fabric which will not require moistening before being used, the process is carried out as follows :I dissolve 16 ounces of a colloid of animal origin, such as gelatin, in 5 pints of water and heat the same up to approximately 140 'F., and maintain the solution at this temperature, as, for instance, in a water bath. Should the gelatin have a tendency to leave an insoluble residue, it is-desirable to strain the solution. After the gelatin has been thoroughly di'ssolved, I add thereto from 18 to 22 ounces of glycerin and 1.5 ounces of a hydroscopic nitrate, such as sodium nitrate,

and mix the parts thoroughly. In a separate vessel I dissolve from .48 of an ounce to .32 of an ounce of a chrome salt, such as bichromate of potash, in "5 pints of water so that the weight of the chrome salt will be between 39 and 3% of the weight of the gelatin. The smaller the percentage of chrome salt, the softer will be the setting of the film. This solution is heated to 1110 IT, and added to the solution of gelatin,

long fiber fabric is run through the solution of gelatin, glycerin, sodium nitrate and bichromate of potash, and then the excess of the solution is squeezed from the sheet, as, for instance, by passing the sheet through cold pressure rollers. The sheet is then hung up a sufficient time to only partially dry and is then again run through the solution of gelatin. glycerin, sodium nitrate and bichromate of potash, and the excess solution removed therefrom. The minimum amount of bichromate of potash and the maximum amount of glycerin should be used to produce the best results. The sheet is then hung up for about twentyfour hours and is then placed upon a suitable non-porous surface, such as glass, and a solution of glycerin is applied thereto by any suitable means, such as a brush or roller. To this'solution, I may add alcohol and aluminum chlorid. The solution which I have found very suitable is one comprising substantially the following proportions, by weight: water, 16 parts; glycerin, 5 parts; alcohol, 1 part; and aluminum chlorid, 1 part. The sheet is then again hung up to dry and may thereafter be cut into the required sizes for use. A stencil fabric pro-' duced by this method, will produce a clear print which is not the case with the stencils of this type heretofore produced, said stencils requiring a number of impressions before beginning to produce a legible print. The film is also kept in such a condition that the type will not out completely through the fabric and block. out inclosed characters.

This application is a division of United States Letters Patent No. 1,092,509, dated April 7, 1914, the a plication forwhich was filed July 1, 1913, erial No. 776,893.

What I claim is 1. The process of producing a stencil fabric which consists in treating a long fiber fabric, first, with a solution of a colloid of animal origin, glycerin, a hydroscopic nitrate and a chrome salt; second, partially drying the fabric; third, again treating the fabric with thesaid solution; fourth, drying the fabric; fifth, applying thereto a solution of glycerin; and sixth, again drying the fabric.

2. The process of producing a stencil fabric which consists in treating a long fiber fabric, first, with a solution of a colloid of animal origin, glycerin, a hydroscopic nitrate and a chrome salt; second, partially drying the fabric; third, again treating the fabric with the said solution; fourth, drying the fabric; fifth, applying thereto a solution of glycerin, alcohol and aluminum chlorid; and sixth, again drying the fabric.

3. The process of producing a stencil fab me which consists in treating a long fiber fabric, first, with a solution of a colloid of animal origin, glycerin, a hydroscopic nitrate and a chrome salt; second, partially drying the fabric; third, again treating the fabric with said solution; fourth, drying the fabric; fifth, applying thereto a solution of glycerin, alcohol and aluminum chlorid in substantially the following proportions, by weight; glycerin, 5 parts; alcohol 1 part; aluminum chlorid, 1 part; and sixt again drying the fabric.

4. The process of producing a stencil fabric which consists in treating a long fiber fabric, first, with a solution of gelatin, glycerin, sodium nitrate and bichromate of potash; second, partially drying the fabric; third, again treating the fabric with the said solution; fourth, drying the fabric; fifth, applying thereto a solution of glycerin; and sixth, again drying the fabric.

5. The process of producing a stencil fabric which consists in treating a long fiber fabric, first, with a solution of gelatin, glycerin, sodium nitrate and bichromate of potash; second, partially drying the fabric;

third, again treating the fabric with the said solution; fourth, drying the fabric; fifth applying thereto a solution of glycerin, alcohol and aluminum chlorid; and sixth, again drying the fabric.

6. The process of producing a stencil fabric which consists in treating a long fiber fabric, first, with a solution of gelatin, glyc erin, sodium nitrate and bichromate of pot ash; second, partially dr ing the fabric; third, again treating the fabric with the said solution; fourth, drying the fabric; fifth, applying thereto a solution of glycerin, alcohol andaluminum chlorid in substantially the following proportions, by weight; glycerin, '5 parts; alcohol, 1 part; aluminum chlorid, 1 part; and sixth, again drying the fabric.

7. The process of producing astencil fabric which consists in ti-eatin a long fiber fabric, first, with a solution of gelatin, glycerin, sodium nitrate and bichromate of potash, in substantially the following proportions by weight: gelatin, 16 ounces; glycerin, 18 to 22 ounces; sodium nitrate 1.5

ounces and bichromate of potash .48 to .32 of an ounce; second, partially drying the fabric; third, again treating the fabric with the said solution; fourth, drying the fabric; fifth, applying thereto a solution of glycerin; and sixth, again drying the fabric.

8. The process of producing a stencil fabric which consists in treating a long fiber fabric, first, with a solution of gelatin, glycerin, sodium nitrate and bichromate of potash in substantially the following proportions, by weight: gelatin, 16 ounces; glycerin, 18 to 22 ounces; sodium nitrate, 1.5 ounces and bichromate of potash .lS to .32

of an ounce; second, partially drying the fabric third, again treating the fabric with the said solution; fourth, drying the fabric;

fifth, applying thereto a solution of glyc-' erin, alcohol and aluminum chlorid; and sixth, again drying the fabric.

9. The process of producing a stencil fabric Which consists in treating a long fiber fabric, first, with a solution of gelatin, glycerin, sodium nitrate and bichromate of potash in substantially the following propor:

tions,'by Weight: gelatin, 16 ounces; glycerin, 18 to 22 ounces; sodium nitrate, 1.5 ounces and bichromate of potash .48 to .32 of an ounce; second partially drying the fabric; third, again treating the fabric with the said solution; fourth, drying the fabric;

fifth, applying thereto a solution of glycerin, alcohol and aluminum .chlorid in substantially the following proportions, by Weight: glycerin, 5 parts; alcohol, 1 part; aluminum chlorid, 1 part; and sixth, again drying the fabric.

In testimony, that I claim the foregoing as my invention, I have signed my name in presence of tWo Witnesses, this twenty-seventh day of January, 1914.

ALBERT E. STRIPPEL. Witnesses:

F. GEORGE BARRY, C. S. SUNDGREN. 

